Laplacian Sharpening

For processing of color images, converting the image from RGB coordinates to either HSI or LAB, processing only the brightness values, recombining the modified brightness with the original color, and converting back to RGB so the result can be displayed is almost always the preferred method. Processing the individual RGB channels alters the proportions of those colors and produces color shifts and distortions that are visually distracting. This interactive tutorial compares the results of sharpening the L channel to the result of sharpening the individual RGB channels.

The tutorial initializes with a randomly selected specimen appearing in the Specimen Image window. The Choose A Specimen pull-down menu provides a broad selection of colorful specimen images, in addition to the initial randomly chosen one. Adjacent to the Specimen Image window is the Laplacian Image window showing the result of applying a Laplacian filter to the specimen. Selecting the LAB Laplacian button displays the result of processing the intensity or luminance information, which preserves the colors of the original specimen image, while selecting the RGB Laplacian button shows the result of individually processing each color channel.